Almost periodic compactifications of group extensions
Let and be groups and let be an extension of by . Given a property of group compactifications, one can ask whether there exist compactifications and of and such that the universal -compactification of is canonically isomorphic to an extension of by . We prove a theorem which gives necessary and sufficient conditions for this to occur for general properties and then apply this result to the almost periodic and weakly almost periodic compactifications of .